#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 1e5+10;
int a[maxn];
int flag[maxn];
int main()
{
	int n;
	scanf("%d",&n);
	int flag = -1;
	for(int i = 0;i<n;i++)
	{
		scanf("%d",&a[i]);	
	}
	if(a[0]!=0) b[0] = a[i]-1;
	else a[i] 
	for(int i = 0;i<n;i++)
	{
		
	}
	
}
